Operation Undergo

Operation Undergo (22 September-1 October 1944) was the 3rd Canadian Division's operation to capture the fortified French port of Calais from its German occupiers, as well as to silence the heavy batteries at Cap Gris Nez to protect the sea approaches to the recently-captured Boulogne-sur-Mer. The Canadians sealed off the town, softened up the defenders with artillery, launched aerial and naval bombardments against Calais, launched infantry assaults supported by armor (including flamethrower tanks), and coordinating artillery rolling barrages. The Canadians attacked Calais from the southwest and cleared the outer defenses of the city's southern and western sides, and the Germans called for a truce; after a misunderstanding, this resulted in the unconditional surrender of all German troops in Calais. At the same time, Cap Gris Nez was also cleared of German forces.